This invention relates to a composite for constructing a molded article wherein this composite includes an igneous rock. More particularly, the invention relates to a composite formed primarily of a basalt igneous rock of varying particle sizes surrounded by a solidified epoxy resin to result in a rigid structure having high strength and superior vibration damping properties than previously attained. The invention further relates to a method for forming a composite of such type.
The prior art teaches the use of polymeric materials to adhere granite chips as fillers into a composite for machine tool beds. Examples of such are a brochure by Ciba-Geigy designated Technical Notes 2/1980, describing an Epoxy "Concrete" wherein a particular epoxy resin is combined with granite aggregates.
In Swiss Patentschrift No. 612 610 a machine support is described which is composed of a mixture of sand and gravel which is bound by a synthetic adhesive agent. The prior art in an article entitled "Methacrylate Resin Concrete" by H. Schulz and G. Nicklau, Werkstatt und Betrieb 115 (1982) 11. refers to the use of methacrylate resin and basalt in the manufacture of surface plates and measuring machine bases. In U.S. Pat. No. 4,382,820 a structural member for a machine tool body is described of the nonmetallic type wherein cement, concrete cement or ceramic is utilized as the base material into which solid objects such as fibers, filaments and metals are placed as reinforcing elements. The grading of aggregates to obtain maximum density of solid material is known and is referred to in an article entitled "Grading Aggregates" in Industrial and Engineering Chemistry Vol. 23, No. 9, pages 1052 to 1058, as well as in the Journal of American Ceramics Society Vol. 44, No. 10, pages 513 to 522, entitled "Mechanical Packing of Spherical Particles".
Nowhere in the prior art is there illustrated the use of igneous rock material in the form of a multiplicity of discrete solid particles of different particle sizes to be compacted in a manner such that a minimum amount and volume of voids are present between the solid particles with these voids being filled with a solidified plastic to result in a rigid article having high strength and high vibration damping properties. Neither does the prior art disclose the use of basalt in a compacted form of solid particles of different size in combination with a plastic resin to result in a molded article with unique features as described herein.
It is an advantage of the present invention to provide a composite for constructing a molded article which employs a unique combination of igneous rock material and a solidified plastic resin. Other advantages are the utilization of an igneous rock material as represented by basalt in combination with a cycloaliphatic epoxy resin to result in a molded article with high strength and vibration damping properties as well as having a smooth and pleasing appearance as it is released from a mold; a unique composite to which additional filler materials can be added that can be formed into a variety of shapes; a method of making molded articles which is easily performed yet does not require special tooling or handling procedures and will result in a composite having a substantially reduced number of voids therein.